Preset optical components in a computer numerically controlled machine

Abstract

A system can include a head of a computer numerically controlled machine configured to deliver electromagnetic energy sufficient to cause a change in a material at least partially contained within an interior space of the computer numerically controlled machine. The system can further include an optical system comprising a plurality of optical elements in the computer numerically controlled machine. The plurality of optical elements can be oriented at a fixed angle to each other to deliver the electromagnetic energy from the head to the material.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims priority to U.S. Provisional Patent Application No. 62 / 426,438 filed on Nov. 25, 2016 and entitled PRESET OPTICAL COMPONENTS IN A CNC MACHINE, the disclosure of which is incorporated herein by reference in its entirety.TECHNICAL FIELD[0002]The subject matter described herein relates to an optical system constructed with optical components that resist misalignment by an end user.BACKGROUND[0003]Optical systems, for example laser-based, computer numerically controlled (CNC) machines, can include one or more optical elements to guide or focus a laser beam. The orientation and optical components can determine where the laser is directed to and the degree to which the laser is focused. In some configurations, optical systems can be adjustable, either by a user or by virtue of their construction.SUMMARY[0004]In one aspect, a system includes a moveable head of a computer numerically controlled machine configured to deliver...

AI Technical Summary

Benefits of technology

The current subject matter can provide advantages by using fixed optical components to prevent misalignment of an optical system during shipping or assembly, and to prevent unintentional misalignment by a user during system setup or use.

Problems solved by technology

While laser cutter / engravers share some common features with CNC machines, they have many differences and present particularly challenging design constraints.

A laser cutter / engraver is subject to regulatory guidelines that restrict the egress of electromagnetic radiation from the unit when operating, making it challenging for light to enter or escape the unit safely, for example to view or record an image of the contents.

The beam of a laser cutter / engraver is easily misdirected, with a small angular deflection of any component relating to the beam path potentially resulting in the beam escaping the intended path, potentially with undesirable consequences.

Airflow is important in laser cutter / engraver designs, as air may become contaminated with byproducts of the laser's interaction with the material such as smoke, which may in turn damage portions of the machine for example fouling optical systems.

Unlike most machining tools, the kerf—the amount of material removed during the operation—is both small and variable depending on the material being processed, the power of the laser, the speed of the laser, and other factors, making it difficult to predict the final size of the object.

Also unlike most machining tools, the output of the laser cutter / engraver is very highly dependent on the speed of operation; a momentary slowing can destroy the workpiece by depositing too much laser energy.

This limitation is modeled in the motion planner and affects the motion plan.

Error conditions can be identified, such as if a foreign body has been inadvertently left in the CNC machine 100, the material has been inadequately secured, or the material is reacting in an unexpected way during machining.

In some implementations, image processing capability can be performed by the CNC machine 100, but with limited speed.

One example of this can be where the onboard processor is slow and can run only simple algorithms in real-time, but which can run more complex analysis given more time.

In these cases, limited image processing can be done locally, with more detailed image processing and analysis being done remotely.

In another example, if the machine is a laser cutter / engraver and activating the laser causes a camera located in the head to become overloaded and useless, footage from that camera may be discarded when it is unavailable.

In another example, recording of video might cease if an error condition is detected, such as the lid being opened unexpectedly during a machining operation.

Another non-encompassing example involves the exit aperture from the laser tube; in the present implementation, the beam is engineered to exit in parallel, however location of the exit aperture may vary due to manufacturing variations, (e.g., laser tube defects).

Also, for the turning mirrors mounted at the fixed angle, they cannot be adjusted to change the fixed angle after being mounted.

For example, the mirror can be mounted in a particular position or orientation during the manufacturing or assembly process, but thereafter, it cannot be adjusted without removing or damaging the turning mirror or the mounting holding the turning mirror.

Over time and repeated use, factors that lead to system wear and tear (including mechanical vibration consistent with normal operation of a CNC machine), can impact the optical alignment system, and may for example, result in misalignment.

If the center of mass is not directly over the optical axis, the system will pivot around the center of mass, resulting in an asymmetric flexing.

This differential in the center of mass between the first mirror mount 810 and the optical system 510 may cause mechanical stress on the optical system 510, for instance, as one side of the first mirror mount 810 pivots about its center of mass and rotates downward over time, thereby causing beam misalignment.

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